Polyethylenimine (PEI) is one of the most potent gene carriers, and the high transfection efficiency of PEI has been postulated to relate to its buffering capacity, which leads to the accumulation of protons bought in by endosomal ATPase and an influx of chloride anions, triggering endosome swelling and disruption, followed by the release of gene drugs such as DNA or siRNA into cytoplasm.
The inventors of the present invention discloses a PAAIO-PEI nanoparticle prepared by using PEI and Fe3O4 as the materials in U.S. patent application Ser. No. 13/074,491 filed on Mar. 29, 2011. The PAAIO-PEI nanoparticle can be a non-viral gene carrier for carrying genetic material, is able to sustain superparamagnetic property, has less cytotoxicity than PEI, and shows better transgene expression efficiency than PEI under the disturbance of fetal bovine serum.
Additionally, Taiwan patent publication No. 201018523 discloses a liposome. For avoiding the activity attenuation of liposome-binding protein which is caused by chemical modification on liposome and reducing the purification steps of the chemically modified liposome, in that patent application, the positive charged polymers (e.g. PEI) and the surfactant polymers are distributed on the neutral lipid membrane with hollow spherical structure via non-covalently bonded combination, to form liposome. However, the patent publication does not overcome the cytotoxicity generated by PEI.
Although PEI has the above advantages and the applications in the prior art, for overcoming PEI's toxicity and owning it high capacity of passing through cellular membrane, the solution to PEI's high toxicity is still a problem necessary to be solved in the clinic application.
It is therefore attempted by the applicant to deal with the above situation encountered in the prior art.